From: Peter Xu <peterx@redhat.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Edward Liaw <edliaw@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH mm-hotfixes-unstable] shmem: fix smaps BUG sleeping while atomic
Date: Wed, 23 Aug 2023 12:41:00 -0400 [thread overview]
Message-ID: <ZOY2nMjTOVe2ozIS@x1n> (raw)
In-Reply-To: <6fe3b3ec-abdf-332f-5c23-6a3b3a3b11a9@google.com>
On Tue, Aug 22, 2023 at 10:14:47PM -0700, Hugh Dickins wrote:
> smaps_pte_hole_lookup() is calling shmem_partial_swap_usage() with page
> table lock held: but shmem_partial_swap_usage() does cond_resched_rcu()
> if need_resched(): "BUG: sleeping function called from invalid context".
>
> Since shmem_partial_swap_usage() is designed to count across a range, but
> smaps_pte_hole_lookup() only calls it for a single page slot, just break
> out of the loop on the last or only page, before checking need_resched().
>
> Fixes: 230100321518 ("mm/smaps: simplify shmem handling of pte holes")
> Signed-off-by: Hugh Dickins <hughd@google.com>
> Cc: stable@vger.kernel.org # 5.16+
Oops.. thanks Hugh.
Acked-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
prev parent reply other threads:[~2023-08-23 16:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-23 5:14 [PATCH mm-hotfixes-unstable] shmem: fix smaps BUG sleeping while atomic Hugh Dickins
2023-08-23 16:41 ` Peter Xu [this message]
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